I was recently installing squid at home as a single caching proxy for all computers in my home network. The simple way is just running squid on your linux router as is and configuring every single browser on all computers in your network so they access internet using squid. That’s doable, but boring. The more interesting way is setting up transparent proxy so all your http traffic goes through squid automatically. I’m not going to explain how to setup the transparent proxy as there are tons of articles in the internet about that, for instance:

The documentation is very straightforward, and has just one problem: it is outdated and doesn’t work with the most recent versions of squid. I’ve read several instructions and was always ending up with these error messages:

Uff that was tough one … If you decided to make your mail communications more secure you probably switched on SSL option in your mail client for POP3/IMAP/SMTP servers. There is a good chance you will get one of those errors that sound like

The server you are connected to is using a security certificare that could not be verified.
A certificate chain processed, but terminated in a root certificate which is not trusted by the trust provider.
Do you want to continue using this server?

I spent way too much time solving the problem because what was just annoying message in Outlook appeared to be serious problem in MacMail. It was not capable of working correctly with that problem. In addition to that I tried to solve the problem using Plesk 8.2 that was a mistake. It appeared that whatever you do with certificates in Plesk that doesn’t affect the mail. So here is the solution for the problem:

As usually there might be a lot of reasons for that. In my case the reason became clear when I checked /var/log/messages:imapd-ssl: /etc/courier-imap/shared/index: No such file or directory problem. The quick and dirty solution appeared to be really quick.

When you need to implement a DNS master/slave relationship, you obviously can go ahead and edit named config files, but when you do next change to DNS configuration using Plesk most your changes will be lost. From the other side Plesk doesn’t provide slave server configuration at all! Here is the solution that works for me on Plesk 8.2. Versions 8.3 and above support the master/slave DNS configuration via web interface.